The present invention relates to an ignition system for an ordnance item and is particularly useful for igniting an aircraft parachute flare which is deployed from an aircraft.
An aircraft parachute flare is normally provided with three sections or components, namely a parachute, a section containing a pyrotechnic composition and an ignition system.
As an aircraft parachute flare is an expendable item, possibly the most important features on these flares are the safety features which attempt to prevent accidental or premature ignition of the pyrotechnic composition. As the illuminating materials which are used in present day flares provide extreme heat upon burning, any accidental igntion of these flares could result in a catastrophic disaster, particularly if the flares are in storage aboard a ship. In order to provide some measure of safety, most present day flares are provided with a safety pin which is kept in position until the flare is mounted in a launching rack on an aircraft. In the event the aircraft returns with flares, the safety pins are reinserted.
In the past, however, primers have been accidentally ignited without actuation of a firing pin. Such detonation can occur, for example, when a device accidentally drops off an aircraft upon a hard landing and, when aboard an aircraft carrier, a dangerous condition is created. Detonation of the primer is normally followed by ignition of an ignition composition which, in turn, ignites the main pyrotechnic charge.
One arrangement for preventing accidental igntion of a pyrotechnic charge such as that occasioned by a fall or drop, is to have one of the elements of a pyrotechnic train out-of-line with the other elements. This out-of-line arrangement prevents a chain reaction of the pyrotechnics element until a sequence of events occur during normal deployment of the ordnance item.
One such out-of-line device is shown and described in U.S. Pat. No. 3,763,785, entitled, "Mal-Assembly Feature For Explosive Train Fuzes", which issued Oct. 9, 1973, to George S. Briggs and Marvin W. Keith, Jr. In this patented device, a portion of the explosive train is contained in an arming rotor and held in an out-of-line safe position until the arming rotor is rotated to an in-line position.
Another out-of-line device is shown and described in U.S. Pat. No. 3,744,425, entitled "Explosive-Disseminator Package", which issued July 10, 1973, to Richard C. Grimm. In this device, chaff is dispensed from a package by explosive action. Detonation of a primer ignites a delay composition, however the delay composition must be slidably moved before a detonator and detonating cord are actuated.